Tamper-proof door lock assembly

ABSTRACT

A door lock assembly including a dead bolt and a knob on the inside of the door for controlling the extension and retraction of the dead bolt. Means secured to the inside surface of the door selectively prevents said dead bolt control knob from rotating to retract said dead bolt from an extended position whereby said door cannot be opened unless said means is positioned so as not to interfere with rotation of said knob to retract the dead bolt.

United States Patent Hollins 1 Nov. 25, 1975 [54] TAMPER-PROOF DOOR LOCKASSEMBLY 3,423,974 1/1969 Bernsley 70/416 Inventor: Jesse R. Quins, 4OStoner Ave. 3,748,882 7/1973 Dusault et al 70/416 Great Neck, N.Y. 11021Primary ExaminerAlbert G. Craig, Jr. [22] Filed: July 5, 1974 21] Appl.NO.2 485,775 [57] ABSTRACT A door lock assembly including a dead boltand a [22] 70/]11065,B7O/447 knob on the inside of the door forcontrolling the 2 2 tension and retraction of the dead bolt. Meanssecured 1 o earc l DI 5 to the inside surface of the door selectivelyprevents 5 R f d said dead bolt control knob from rotating to retract 1e erences said dead bolt from an extended position whereby said UNITEDSTATES PATENTS door cannot be opened unless said means is positioned756,064 3/1904 Sherman 70/429 so as not to interfere with rotation ofsaid knob to re- 840,711 1/1907 Puttcamp et al... 70/429 tract the deadbolt.

1,700,135 1/1929 Lanes 70/416 3,263,462 8/1966 Suroff et a1. 70/447 1Claim, 5 Drawing Figures US. Patent Nov. 25, 1975 3,921,423

TAMPER-PROOF DOOR LOCK ASSEMBLY BACKGROUND OF THE INVENTION 1. Field ofthe Invention Tamper-proof door lock 2. Description of the Prior ArtMany doors include a mortice-type door lock mechanism. A mortice-typedoor lock mechanism includes a door latch which is secured to the door.A lock plate is located on the door frame and includes a latchreceptacle for the latch. When the latch is received within the latchreceptacle the door cannot be opened. On the other hand, when the latchis retracted from the latch receptacle, the door can be opened. Usuallya lock cylinder is provided so that if the appropriate key is insertedthereinto from the outside of the door the latch can be withdrawn byrotating the key enabling the door to be opened. The door. of course,can be opened from the inside by rotating the inside door knob.

A mortice'type lock unit includes two pins within the lock mechanismwith each pin extending to the lateral edge of the door. By pushing oneof the pins the latch cannot be retracted upon the outside door knobbeing rotated. By pushing the other pin, the latch is retracted upon theoutside door knob being rotated.

While the mortice-type lock hereinbefore described provides an adequatemethod of securing a door, the lock can be picked, i.e., illicitlyopened by using a mas ter key or lock picking tool to open the lockcylinder.

In an attempt to prevent illicit opening of a door, many people use adead bolt lock assembly which acts as an additional means for preventingthe illicit opening of the door. The dead bolt lock assembly includes adead bolt which can be extended outwardly from a door into a dead boltreceptacle in the door frame by rotating a knob located on the insidesurface of the door. A lock cylinder is provided so that the dead boltcan be retracted by a person extending a key into said lock cylinderfrom the outside surface of the door. When the dead bolt is retracted,the dead bolt assembly does not prevent the door from being opened.However, when the dead bolt is extended so as to extend into the deadbolt receptacle, the door cannot be opened even if the mortice-type locklatch is retracted, i.e., is not received in the latch receptacle.

A problem that exists with a dead bolt type lock assembly is that by useof a pass key or lock picking tool it is still possible for a person toillicitly retract the dead bolt so that it is no longer in the dead boltreceptacle whereby if the latch is retracted the door can be illicitlyopened.

SUMMARY OF THE INVENTION 1. Purposes of the Invention It is an object ofthe present invention to provide improved means for securing a dooragainst illicit opening.

Another object of the present invention is to provide a tamper-proofdoor lock which prevents the illicit retraction ofa door dead bolt fromthe dead bolt receptacle in the door frame.

Another object of the present invention is to provide apparatus forprecenting the illicit retraction of a dead bolt from the dead boltreceptacle which apparatus is controlled by means attached to the insidesurface of the door.

Still another object of the present invention is to provide means forpreventing a key from turning the lock mechanism thus retracting thedead bolt from its receptacle wherein said means is attached to theinside surface of the door and can easily be placed in selectiveoperation.

Yet another object of the present invention is to provide apparatus forpreventing the illicit retraction of a door dead bolt from a doorreceptacle wherein said apparatus can be attached to the inside surfaceof a door and can be economically manufactured and is easy to utilizeOther objects of the invention in part will be obvious and in part willbe hereinafter pointed out.

2. Brief Description of the Invention According to the presentinvention. the foregoing as well as other objects are achieved by a deadbolt knob lock which consists of a housing that is affixed to the insidesurface of a door. Affixed to said housing is a swing plate which has afirst position wherein said plate is spaced from the dead bolt knob. Inthe second position the plate is located immediately above the dead boltknob and prevents the same from rotating so that even if a key or toolis inserted into the lock cylinder for the dead bolt from outside of thedoor, the dead bolt cannot be rotated inasmuch as this is prevented byabutment by said dead bolt knob with said plate.

The invention accordingly consists in the features of construction.combination of elements and arrange ment of parts which will beexemplified in the device hereinafter described and of which the scopeof application will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a partially broken front elevational view of a conventionalmortice-type lock and a conventional dead bolt lock assembly;

FIG. 2 is a side plan view of a door having a conventional mortice-typelock assembly and a conventional dead bolt lock assembly utilizing thedead bolt control mechanism of the present invention;

FIG. 3 is a sectional view taken substantially along the line 3-3 ofFIG. 2;

FIG. 4 is an enlarged sectional view taken substantially along the line4-4 of FIG. 3; and

FIG. 5 is an enlarged sectional view taken substantially along the line55 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 of the drawings aconventional prior art mortice-type lock and dead bolt lock assemblystructure 10 on door 12 is shown. Door 12 cooperates with door frame 14in the conventional manner. A door knob 16 is provided on the outside ofthe door which is shown in FIG. 1 of the drawings. Door knob 16 isaffixed to mortice lock assembly housing 18. A latch 20 is provided.Latch 20 can be extended and retracted as will hereinafter be described.Mortice-type lock assembly includes pins 22 and 24. Upon pin 22 beingdepressed rotation of knob 16 results in latch 20 being retracted sothat the door can be opened. On the other hand, when pin 24 is depressedrotation of the door knob on the outside of the door does not result inlatch 20 being retracted.

Secured to door frame 14 is a lock plate 26. Screws 28 and 30 extendthrough clearance holes in lock plate 3 26 and are in threadedengagement with frame 14 to prevent lock plate 26 from moving. Lockplate 26 includes a latch receptacle which receives latch in theconventional manner.

A dead bolt assembly 32 includes a knob 34 and a dead bolt 36. Plate 26includes an opening to which a dead bolt receptacle '38 extends. Withknob 34 in the vertical position shown in FIG. 2. dead bolt 36 is in theretracted position. i.e.. said dead bolt does not extend into dead boltreceptacle 38. On the other hand. with knob 34 rotated clockwise ninetydegrees from the position shown in FIG. 2, looking at the rear of saiddead bolt assembly. dead bolt 36 is in receptacle 38 so as to preventdoor 12 from being opened.

A key and lock cylinder arrangement is provided and includes a keyreceiving opening 41 on the outside of door 12. Upon the appropriate keybeing received in key receiving lock cylinder opening 41 and rotated.dead bolt 36 can be retracted and during said retraction knob 34 isrotated. A lock cylinder 44 is provided and includes an opening forreceiving a key on the outside of the door so that upon the properinsertion of a key in said lock cylinder and rotation thereof the latch20 can be retracted as necessary.

The aforedescribed structure is conventional and enables a person to usetwo locking means to secure a door. However. a pass key or pick may beused by someone to retract dead bolt 38 by being inserted in lockcylinder opening 41. Similarly. a pass key or pick may be inserted inlock cylinder 44 to retract latch 20. If all of the foregoing is done.door 12 can be illicitly opened.

In the drawings a dead bolt knob lock housing is shown and includessections 48 and 50 which extend perpendicularly away from the door.Sections 48 and 50 are parallel to each other and spaced apart from eachother and joined at their inside portions by a verti cal side. Section48 includes a central opening 52. In a similar fashion. section 50includes a central opening 54. It is to be appreciated that openings 52and 54 are in'registry with each other with opening 52 being larger thanopening 54. A rivet 56 extends through openings 54 and 52 and includes ahead 58 which rests on the outer surface of section 48 and a curled-overend 60 which abuts the outer surface of section 50. A compression spring62 surrounds rivet 56 in opening 52 and the upper end of said springabuts head 58. A swingable pivot plate 64 is provided and a portion ofsaid plate extends into the space between sections 48 and 50. Pivotplate 64 includes an opening through which rivet 56 extends.

The bottom end of compression spring 62 abuts pivot plate 64 so as tourge said pivot plate in contact with section 50 to prevent said pivotplate from freely pivoting. Pivot plate 64 is generally rectangular inconfiguration and can be swung between the alternate positions shown indotted and solid lines in FIG. 4.

Pivot plate 64 when in the solid position shown in FIG. 4 is above asection of knob 34 so as to prevent the same from being rotated in acounterclockwise direction from the horizontal position in which thedead bolt is extended so as to move the dead bolt from a lockingposition to a non-locking position. Extending through I 4 76 extendthrough section 48 with the ends of said bolt clearance hole furthestfrom the door plate each being countersunk. Screws 78 and 80 extendthrough bolt clearance holes 74 and 76 respectively and are in threadedengagement with the door.

In attaching the dead bolt knob lock to door 12 care must be taken sothat said knob lock is positioned whereby plate 64 can be swung so thata portion of said plate is immediately above a section of knob 34 whenthe knob is in the horizontal position (see FIG. 5).

If a person wishes to insure that the dead bolt is placed in a lockedcondition and cannot be unlocked. knob 34 is rotated to the horizontalposition shown in FIGS. 3, 4 and 5 whereby the dead bolt is extended andreceived in dead bolt receptacle 38. Plate 64 is then swung to theposition shown in solid lines in FIG. 4 overlaying a portion of knob 34and thereby preventing the knob from being rotated in a counterclockwisedirection and retraction of the dead bolt.

Even if somebody has the key for lock cylinder 40 they still will not beable to retract the dead bolt inasmuch as knob 34 is prevented fromrotating by plate 64. Obviously a pick will be of no assistance to aperson seeking to illicitly retract the dead bolt inasmuch as even ifthe pick is successfully used to rotate lock cylinder 40, knob 34 cannotrotate since it will abut plate 64 thereby preventing the dead bolt frombeing retracted.

When a person leaves the premises in which door I2 is installed. plate64 is swung to the position shown in dotted lines in FIG. 4, i.e. out ofthe way of knob 34. Thusthe person upon returning to the premises canuse his key to open lock cylinder 40 and rotate knob 34 to retract thedead bolt.

The parts may be made of suitable materials such as metal. plastic. etc.

The invention accordingly consists in the features of construction.combination of elements and arrangement of parts which will beexemplified in the device hereinafter described and of which the scopeof application will be indicated in the appended claims.

Having thus described the invention there is claimed as new and desiredto be secured by Letters Patent:

1. A door lock assembly comprising a door. a door frame. a dead boltassembly secured to said door. said dead bolt assembly including a deadbolt. an oblong knob having an elongated axis on the inside surface ofsaid door and rotatable for controlling the extension and retraction ofsaid dead bolt, a lock cylinder having an opening on the outside surfaceof said door for receiving a key for controlling the extension andretraction of said dead bolt. said door frame including a dead boltreceptacle. a housing affixed to said door on the inside surfacethereof. said housing including two spaced apart parallel sections witha gap extending between said sections. a first of said sectionsincluding an opening extending there through, a second of said sectionsincluding an opening extending there through and in alignment with saidopening extending through said first of said sections, means boltingsaid first section to said door and means bolting said second section tosaid door, a member extending through said openings. a pivot platehaving an opening and pivotable about said member in said gap, a springhaving two ends surrounding said member and affixed at one end of saidmember and abutting said pivot plate at said other end whereby saidpivot plate is prevented from freely moving, said pivot plate having aflat rectangular configuration, said pivot plate having a first andsecond position, said pivot and in said second position spaced from saidknob to enable said knob to be rotated. said pivot plate in said firstand second positions being in a single plane.

1. A door lock assembly comprising a door, a door frame, a dead boltassembly secured to said door, said dead bolt assembly including a deadbolt, an oblong knob having an elongated axis on the inside surface ofsaid door and rotatable for controlling the extension and retraction ofsaid dead bolt, a lock cylinder having an opening on the outside surfaceof said door for receiving a key for controlling the extension andretraction of said dead bolt, said door frame including a dead boltreceptacle, a housing affixed to said door on the inside surfacethereof, said housing including two spaced apart parallel sections witha gap extending between said sections, a first of said sectionsincluding an opening extending there through, a second of said sectionsincluding an opening extending there through and in alignment with saidopening extending through said first of said sections, means boltingsaid first section to said door and means bolting said second section tosaid door, a member extending through said openings, a pivot platehaving an opening and pivotable about said member in said gap, a springhaving two ends surrounding said member and affixed at one end of saidmember and abutting said pivot plate at said other end whereby saidpivot plate is prevented from freely moving, said pivot plate having aflat rectangular configuration, said pivot plate having a first andsecond position, said pivot plate in said first position abutting aportion of said oblong knob parallel to said elongated axis andpreventing said knob from rotating to retract said door bolt from anextended position to a retracted position, and in said second positionspaced from said knob to enable said knob to be rotated, said pivotplate in said first and second positions being in a single plane.